1. Field of the Invention
The invention relates to a process for producing a glass body and somewhat more particularly to a method of producing a preform for drawing into a glass light waveguide.
2. Prior Art
A process for optical fiber fabrication wherein silicon-organic materials are chemically converted into glass is known, for example from Electronic Letters, Vol. 18, (1982) pages 499-500. This process adapts a glass production process known as the so-called "sol-gel process" for optical fiber fabrication.
In other known optical fiber fabrication processes (see, for example, Chem. Engineering Technology, Vol. 51, (1979) pages 612-627) preforms for drawing into glass fiber light waveguides are produced by depositing glass from a gaseous phase. High-grade fibers are produced by this technique, however, the production rate is quite low. The rate at which a fiber preform can be produced by depositing glass from a gaseous phase limits the production rate. Maximum rates of about 5 km/h, expressed in equivalent fiber length, have been attained.
Processes of the type initially referred to, which bypass the gaseous phase are suitable for higher production rates. With known processes of this type, one begins from a silicon alkoxide, i.e., from a silicon-organic material, which is hydrolyzed in its liquid phase and is jelled into a large volume body by means of polycondensation of silicic acid. A glass body can be produced from the resultant gel by means of drying and sintering. Preforms having desired gradient profiles, however, are difficult to produce with this technique.